Quote from: gmaxwell on April 11, 2017, 10:49:54 PM

Quote from: piotr_n on April 11, 2017, 10:24:52 PM

I think what tomtomtom7 is trying to say is that the common approach (used not only by core) is that even though the node verifies the transactions before a block is announced, the actual moment when the UTXO database is updated (and the changes committed to it) is during the block's validation.

That is what I understand him to be saying, but it isn't true for Bitcoin Core. For Core, the moment when the UTXO database is updated/and changes committed is _not_ during block validation. It's after in separate batch steps which apply big batches of changes at a time; specifically to mostly get interacting with the database out of the critical path.

This is also why if you shut your node off uncleanly you'll see it going and reprocessing dozens of blocks-- their effects hadn't been applied to the database yet.

I don't understand the specifics of the code, so can you enlighten me? What you're saying sounds like semantics: "It's after in separate batch steps" sounds like it is still done when a block validates, just maybe not part of a certain function. I mean, it has to be done before the next block anyway. Is the UTXO updated before the node officially validates the block??

It sounds like this new way validates the TX as they happen, and this saves time later. I wish people could be a little more specific in a tech sub-forum -like with code snippets.